Preparation of 2-picoline sulfur condensation products



Patented Feb. 7, 1950 PREPARATION 'OF arthonmt SULFUR CONDENSATION raonnocrs Helenii. Thayer, Pittsburgh, Pa., assignor to Koppers Company, Inc, Pittsburgh, Pa, a cor-pcration of Delaware No Drawing. Continuation of application'- Serial -No. 665,638, April 27, 1946.

This application February 26, 1948, Serial No. 11,317

The present invention relates'to condensation products of Z-picoline and sulphur, and to the process for their synthesis.

It is known to sulphurate mi'x'turesof tar bases, for example, mixtures of pyridine and quinoline and their respective homologues. The 30-01)- tained sulphurated mixtures of black pitch-like products have been used in the past without separation of individual ingredients. More recently it was found that all of the constituents of said tar bases do not react with sulphur. For example 3-pico1ine can be separated substantially unchanged when a close-boiling tar base mixture, comprising 3- and 4-picoline and 2,6-lutidine, is treated with sulphur or sulphur halides to condense the 4-picoline and 2,6-lut'idine as a black insoluble mass.

It has now been found that when 2-, 3-, and -picolines are reacted with sulphur under similar temperature conditions, the reactio'ris occur ring and the products obtained are altogether diiferent. Th said reaction with 4-picoline and novel reaction product produced thereby is disclosed and claimed in an application of James L. Keller, Serial No. 536,280, filed May 19, 1944.

The primary object of the present invention is the provision of novel compounds thatare the condensation reaction products of 2-picoline and sulphur. I

Another object of the invention is the provision of a novel process for the synthesis of condensation products of sulphur and 2-picoline.

The invention has for further objects such other improvements as may be found to obtain in the processes and products hereinafter de= scribed or claimed.

The present invention comprises reacting 2- picoline with sulphur in the presence of small amounts of sodium hydroxide at elevated temperatures and the production thereby of a series of novel condensation products including the ultimate product of condensation Cs'efiziN sz which is a bright orange-yellow solid "and the intermediate condensation products, CuHmNh and C18H13N3. Sym-di-(pyridyI-Z) ethylene, a known compound, is also produced in small amounts as an intermediate condensation prod not of the reaction. The ncsve cqn'densauon product CIZHIZNE has been identified to be di (pyridyl-Z) -ethane The above mentioned prod nets are separated from the r'ea'ctionmass by addition thereto of mineral acid, whereby the condensation products are dissolved andu'nre acted sulphur separated and filtered; "the filtrate therefrom is partially 'iieutraliz'ed with alkali 7 Claims. (Cl. 260-290) metal hydroxide whereupon the condensation product C3sH24NsS2 is then precipitated. The intermediate condensation products are salted out as an oil from the filtrate and then separated by distillation. It is important to the production of the aforesaid condensation products that the condensation reaction be performed at a temperature less than 200 C. and preferably between 155 and 165 C.

. The products of invention can be useful in a number of different fields, for example, as inter mediates in the preparation of other chemical compounds, such as pharmaceuticals, as valuable ingredients in pest control compositions, as inhibitors where materials are treated with acids, and as chemicals useful in the vulcanization of rubber.

phur.

, The following is an example of operation or the novel process for producing the condensa tion products of invention. A mixture of 1000 grams of Z-picoline having a 2 boiling range, 500 grams of finely divided sulphur and 3.0 grams of sodium hydroxide was heated under refiux for 34 hours at a temperature between 155 and 165 C. Quantities of hydrogen sulphide were given oif during the reaction. After cooling the reaction mixture, it was dissolved in 1200 ml. of 50% sulphuric acid and was filtered. The precipitate consisted chiefly of unreacted sul-- The filtrate was then neutralized to a degree of mild acidity by gradual addition thereto of 2000 ml. of 50% sodium hydroxide, the temperature being maintained at 25 C. or less by artificial cooling. This neutralization elfected'a precipitation of orange-yellow solid, which was filtered from the mixture. Neutralization of the acid filtrate was continued until the mixture closely approached the neutral point, during which time the mixture was twice filtered for separation of further quantities of precipitate.

The slightly acid filtrate was then made alkaline whereupon a brown oil separated. This oil is salted out of the aqueous solution by the presence therein of sodium sulphate formed by the acidification and neutralization steps. The separated oil and the aqueous alkaline layer were Average Found The molecular weight was determined to be about 609. From the preceding determinations and from analogous organic reactions, it was determined that the product of condensation has the formula Gael-124N832 with a melting point range of 200-203.5 C.

The oily product in the ether extract was distilled at atmospheric pressure for removal of the ether, and then fractionally distilled under vac uum to provide a fraction containing 160.? grams and boiling in the range of 164 to 180 C. under a vacuum of mm. Hg absolute pressure, an other fraction of 22 grams being sym-di(pyridyl- 2) ethylene and boiling in the range of 186 to 212 C. (at 14 mm. Hg absolute pressure) and a third fraction of 1228 grams boiling in the range of 215 to 255 C. at 2 mm. Hg. The relative weight of elements in the compound of the first fraction was found after purification by repeated recrystallizations to be as follows:

Average Found Carbon Hydrogen Nitrogen Average Found Carbon Hydrogem Nitrogen r Its molecular weight was determined to be 271.4 and it was concluded that the compound is of the formula, C18H13N3. In purified state, it is a yellow crystalline solid having a melting point of 102.5 to 103 C. Its behavior demonstrates that the compound is a condensation of three picolines in an azole ring. Two moles of the compound When heated with a further quantity of sulphur condense with evolution of hydrogen sulphide to form the aforesaid sulphur-bearing condensation product C3GH24N6S2. The reverse transformation can be accomplished by treating C3GH24N6S2 with a reducing agent such as zinc and acid or dihydro-anthracene.

The invention as hereinafter set forth is embodied in particular form and manner but may be variously embodied within the scope of the claims hereinafter made.

The present application is a continuation of my application Serial No. 665,638, filed April 27, 1946, now abandoned.

I claim:

1. A process of producing novel condensation products of 2-picoline and sulphur, comprising: heating a mixture of 2-picoline and sulphur to form condensation products comprising a mixture of individual sulfurated and nitrogenated heterocyclic compounds; dissolving the crude reaction product in acid and separating acid-insoluble material from acid solution; neutralizing the acid solution by a plurality of additions thereto of an alkali and thereby separating one condensation product; after complete neutralization, extracting an oily product from the neutralized solution; fractionally distilling the soseparated oily product and recovering nitrogenated hydrocarbons as pure products.

2. A process of producting novel condensation products of Z-picoline and sulphur, comprising: heating a mixture of 2-picoline and sulphur at a temperature between and C'. for about 24 to 30 hours to form condensation products comprising a mixture of individual sulfurated and nitrogenated heterocyclic compounds; dissolving the crude reaction product in acid and separating acid-insoluble material from acid solution; neutralizing the acid solution by a plurality of additions thereto of an alkali and thereby separating one condensation product; after complete neutralization, extracting an oily product from the neutralized solution; fractionally distilling the so-separated oily product and recovering nitrogenated hydrocarbons as pure products.

3. A process of producing novel condensation products of 2-picoline and sulphur, comprising the steps of heating a mixture of 2-picoline and sulphur at a temperature between 155 and 165 C. for about 24 to 30 hours and separating pure products from the reaction mass produced thereby.

4. A process of producing novel condensation products of 2-picoline and sulphur, comprising: heating a mixture of Z-picoline and sulphur to form condensation products comprising a mixture of individual sulfurated and nitrogenated heterocyclic compounds; dissolving crude product in acid and separating acid-insoluble material from acid solution; partially neutralizing the acid solution and thereby precipitating a condensation product; and recrystallizing the condensation product from a suitable solvent and obtaining an orange-yellow crystalline product having a melting point of 200-203.5 C. and the formula C36H24N6S2- 5. A process of producing novel condensation products of 2-picoline and sulphur, comprising: heating a, mixture of 2-picoline and sulphur at a temperature between 155 and 165 C. for about 24 to 30 hours to form condensation products comprising a mixture of individual sulfurated and nitrogenated heterocyclic compounds; dissolving crude product in acid and separating acid-insoluble material from acid solution; partially neutralizing the acid solution and thereby precipitating a. condensation product; recrystallizing the precipitated condensation product from a suitable solvent and obtaining an orange-yellow crystalline product having a melting point of 200-203.5 C. and the formula C36H24NsS2; completing neutralization of the said solution and thereby salting out an oily mixture of condensation products; extracting the oily mixture from 75 the said solution; and thereafter fractionally distilling the extracted oil to recover condensation products including sym-di-(pyridyl-2 ethane.

6. A process of producing novel condensation products of 2-pico1ine and sulphur, cozno sin heating a mixture of Z-picoline and sulp temperature between 155 and 165 C. for a so" 24 to 30 hours to form condensation IJTGCiLcLL comprising a mixture of individual sulfurated and nitrogenated heterocyclic compounds; dissolving crude product in acid and separating aeid-inso1- uble material from acid solution; partially neutralizing the acid solution and thereby precipitating a, condensation product; recrystallizing the precipitated condensation product from a suitable solvent and obtaining an orange-yellow crystalline product having a melting point of 200 203.5 C. and the formula C3cH24NsS2; completing neutralization of the said solution and thereby salting out an oily mixture of condensation products; extracting the oily mixture from the said solution; and thereafter iractionally distilling the extracted oil to recover condensation products including sym-di(pyricly1-2) ethane and a compound having the formula CisHisNs, a melting point range of l02.5 to 103 0., and a conformation of three picoline structures composing conjointly a ring.

7 A 2-picoline condensation product of meltpint range 200" to 203.9 C. and a molecular nt of about 609 produced by condensing a. ;ture of 2 picoline and sulphur when heated to a temperature of 155 to 165" C. for a period of 24 to 36 hours, dissolving the condensate product in acid and filtering oil the acid-insoluble material, neutralizing the filtrate to precipitate the condensation product and recrystallizing the condensation product With a solvent.

HELEN I. THAYER.

CITED he following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Dietrich Apr. 30, 1940 

1. A PROCESS OF PRODUCING NOVEL CONDENSATION PRODUCTS OF 2-PICOLINE AND SULPHUR, COMPRISING: HEATING A MIXTURE OF 2-PICOLINE AND SULPHUR TO FORM CONDENSATION PRODUCTS COMPRISING A MIXTURE OF INDIVIDUAL SULFURATED AND NITROGENATED HETEROCYCLIC COMPOUNDS; DISSOLVING THE CRUDE REACTION PRODUCT IN ACID AND SEPARATING ACID-INSOLUBLE MATERIAL FROM ACID SOLUTION; NEUTRALIZING THE ACID SOLUTION BY A PLURALITY OF ADDITIONS THERETO OF AN ALKALI AND THEREBY SEPARATING ONE CONDENSATION PRODUCT; AFTER COMPLETE NEUTRALIZATION, EXTRACTING AN OILY PRODUCT FROM THE NEUTRALIZED SOLUTION; FRACTIONALLY DISTILLING THE SOSEPARATED OILY PRODUCT AND RECOVERING NITROGENATED HYDROCARBONS AS PURE PRODUCTS. 